Conventionally, as a kind of test apparatus, for example, a test circuit is proposed in Patent Literature 1. In the test circuit, a switch, a coil, and a semiconductor element are connected in series to a power source. In this configuration, a diode element is disposed to configure a loop path along with the coil. In this case, the loop path is configured when the switch and a switching element configuring the semiconductor element are switched off. A cathode electrode of the diode element is connected to a positive electrode of the power source.